The present invention relates generally to a medical device for measuring sexual function.
Sexual dysfunction (SD) is defined as the difficulty experienced by an individual or a couple during any stage of a normal sexual activity. Erectile dysfunction (ED) can be defined as the inability to obtain and/or maintain a penile erection sufficient for intercourse. ED may result from arterial, cavernosal/venous, neurologic, hormonal, autonomic, pharmacologic and/or psychological factors. SD and ED are prevalent conditions and are associated with poorer quality of life metrics. Furthermore, secondary analysis from the Prostate Cancer Prevention Trial (PCPT) trial showed that men with ED without a history of cardiovascular disease were at 45% increased risk of having a subsequent cardiovascular event, and this finding has been confirmed in many other studies (Thompson JAMA 2005).
The diagnosis of SD and ED relies in large part on patient-derived history and self-administered questionnaires. There are a few clinical diagnostic instruments used in the diagnostic evaluation of erectile dysfunction, but they are not commonly used due to expense, patient discomfort, lack of useful diagnostic information yielded, and/or invasiveness.
For instance, large epidemiological studies on the prevalence and predictors of sexual dysfunction have relied on patient-reported questionnaires and not on diagnostic instruments (Laumann et al. JAMA 1999; 281(6):537-544) (Burke J P et al J Urol 2007 April; 177(4):1438-42). The prevalence and predictors of sexual dysfunction due to medical-related treatments, such as radiation or surgical treatment for prostate cancer, is of particular interest. These studies have relied on demographic information and patient-reported measures of sexual health-related quality of life domains to assess the impact of treatment to sexual function (Kuban et al. JAMA 2011; 306(11):1205-1214) (Steineck et al. NEJM 2002; 347(11):790-6). Finally, large randomized, controlled trials require metrics to assess whether treatment improves erectile function. The major randomized control trials have used pretreatment and post-treatment diaries, or questionnaires such as the International Index of Erectile Function (Goldstein et al. NEJM 1998; 338:1397-1404) (Padma-Nathan et al. NEJM 1997; 336:1-7) (Brock et al. J Urol 2002 October; 168(4 Pt 1): 1332-6).
Thus, while patient-reported symptoms are a key element of overall sexual heath, there is a need for objective and reproducible data on sexual function. Such data would allow for better characterization of the prevalence and predictors of sexual dysfunction, enhance the understanding of treatment-related effects on erectile function, improve the ability to accurately compare the effectiveness of treatments for ED, and offer an objective tool for assessing increased risk of cardiovascular disease.
Currently available diagnostic tools and instruments to assess for SD and ED are limited by the conditions required to obtain data, invasiveness, and by the amount of useful information they provide, which are all reasons for why they have not been utilized in major studies. The best objective test for ED is performed by intracavernosal injection of a vasoactive substance into the penis while the patient is at a doctor's office, followed by measuring the velocities of the blood flow in the cavernosal arteries within the penis using a hand-held Doppler ultrasound device. This test is invasive, does not provide relevant situational (in vivo) data, and is not frequently a part of an ED work-up as it rarely changes clinical management. There is no commonly accepted work-up of SD or assessment of mechanical or hemodynamic parameters of the clitoris in females beyond patient interviews and questionnaires.
Another technology presently used to measure penile blood flow is the color duplex ultrasound in hand-held devices. This method utilizes high resolution, real-time ultrasonography and color-pulsed Doppler to visualize arterial and venous flow. Hand-held ultrasound measurement devices are limited by the angle of incidence and user experience, which can cause variability and imprecision inherent in a hand-held device. Other inventions address this method by placing the transducer on an apparatus that fits onto the penis.
An apparatus for penile hemodynamic monitoring using ultrasound typically uses an ultrasound generator, display, and adjustable clamp around the penis, such as those disclosed in U.S. Pat. Nos. 5,931,783, 6,221,021, 6,814,702, and 5,947,901, and U.S. Patent Application Pub. No. 2007/0129635. The user applies an ultrasound coupling gel to the surface of the penis, and places the apparatus around the penis. The user holds the apparatus in place while ultrasound energy is delivered to the penis. The energy is able to monitor and/or stimulate hemodynamic activity such as blood flow to the penis. However, the apparatus is bulky and requires the user to hold the apparatus in place. It also requires frequent adjustment to allow for adequate coupling of the sensors to the skin. For these reasons, this limits when and where the apparatus can be used, and prohibits real-time data collection during intercourse, which would most accurately represent the patient's disease, which is private in nature. In summary, this apparatus cannot provide true in vivo data of how an erection performs during sexual intercourse.
A smaller device has been described in U.S. Pat. No. 6,251,076 that includes fixed transducers aligned for Doppler ultrasound measurements of the cavernosal arteries. This is an office-based device that is secured to the penis with a fixing device. The device can be used with vasodilating agents to measure peak systolic and end diastolic velocities and resistive indices. This device, while smaller, is still bulky, has rigid components, and requires a supervising physician to operate and interpret the information. It also provides pulse oximetry data based on the transducers but if these are not placed precisely over the arteries, it cannot obtain any useful information. Again, this apparatus cannot provide true in vivo data of how an erection performs during sexual intercourse.
Another apparatus to measure penile rigidity and arterial-venous flows disclosed in U.S. Pat. No. 4,747,415 and U.S. Patent Application Publication No. 2010/0016759 uses pressure transducers to measure intracavernous pressure and pulse pressure of the penis. The sensor is paced around the penis and the measurements are collected during both day and night. Similar to a blood pressure cuff placed on the arm, the device comprises a cuff with a band and velcro strap. It can only measure the radial rigidity of the penis, and requires an experienced user to operate. It does not measure penile axial buckling forces. This apparatus also cannot provide true in vivo data of how an erection performs during sexual intercourse.
Another apparatus is the Nocturnal Penile Tumescence and Rigidity (NPTR) monitoring device disclosed in U.S. Pat. Nos. 4,606,353 and 6,162,188, which contains two loops placed at the base of the penis and near the end of the penis that measure axial rigidity. This device is used to distinguish between organic and psychogenic causes of erectile dysfunction. Patients with organic dysfunction will not have erections at night. Patients with psychogenic causes of erectile dysfunction are able to have erections at night. The treatment of erectile dysfunction in each group is different. While this data may be beneficial for a select subset of patients, the data from this apparatus is limited and may not be reproducible while the user is awake and during attempted sexual intercourse. Measurements are obtained overnight while the user is asleep using an automated, portable device. The NPTR device includes a sensor for photoplethysmography. It only measures the radial rigidity of the penis, and requires an experienced user to operate. It does not measure penile axial buckling forces. The device is cumbersome and may require the patient to stay overnight at a monitored facility. It also does not provide in vivo data of how an erection performs during sexual intercourse.
Another apparatus is the Rigidometer disclosed in U.S. Patent Application Pub. No. 2010/0217150, which consists of an instrument that measures penile rigidity by pressing the instrument against the penis for a predetermined period. A visual digital readout indicates the cavernosal pressure of the penis. The penis is placed within a separate instrument while the penis is erect. This provides data on penile axial buckling forces but does not measure the radial rigidity of the penis.
Another apparatus disclosed in U.S. Pat. No. 7,390,297 attempts to relieve erectile dysfunction by having a restricting band at the base of the penis to prevent blood from leaving the penis. The device has a temperature gauge that measures the temperature of the scan, and the results can be interpreted visually while worn and monitored. The temperature is displayed using a thermochromic surface, which changes color based on contact with a surface. This device provides no objective numerical data. Further, these devices are not frequently used as they cause painful ischemia that is not relieved by the fixed source of blood flow obstruction, in this case the ring. Although the thermochromic surface attempts to give some feedback, this is an open feedback loop that relies on the user taking off the device as a crude binary on/off modulation.
Another apparatus disclosed in EP1054626 measures changes in clitoral, vaginal-artery, and/or vaginal-capillary blood flow, clitoral engorgement, and bioimpedance. It includes an ultrasound transducer, oximeter probe near the vaginal wall, audio feedback, pH measurement, control electronics, with the housing to be placed within the vagina. The major limitation of this device is that it is bulky and cannot be used during penetrative intercourse.
None of the above devices are able to adequately and objectively measure penile or clitoral rigidity, blood flow, and temperature during the acts of masturbation or coitus. In addition, none of the disclosed devices provide real time, in vivo data to the user, health care professionals, or researchers. The above devices are invasive, cumbersome, and bulky for the patient. Further, a majority of the above devices require trained, experienced personnel to place, position, and operate. In addition, the above devices only provide a partial characterization of the penile/clitoral erection, and thus, multiple devices and simulations must be required to obtain adequate objective data. All of the devices have multiple wired connections to the apparatus that is placed on the penis, which adds to the bulkiness and invasiveness of the instrument. Furthermore, none of these devices have the ability to improve erectile function through a closed feedback loop providing a non-painful erection that can be used during coitus. Likewise, none of the devices provide a back-end mechanism for transmitting real-time data to another device for analysis or transmitting and de-identifying data for research or clinical use on a large scale.